


Rewrite the Stars

by Moon_Willow_23



Series: Galaxy Brain [2]
Category: Marvel Cinematic Universe, X-Men (Movieverse), X-Men - All Media Types
Genre: Erik Lehnsherr Loves Charles Xavier, Erik Logic Is The Best Logic, Erik is a Sweetheart, Mentions of Psychic Bonds, Mpreg, Multi, Prom, Protective Sean Cassidy, Protective Siblings, Siblings Who Are Done With Everything, how they got together, oblivious crushes
Language: English
Status: Completed
Published: 2020-07-09
Updated: 2020-07-09
Packaged: 2021-03-04 19:15:02
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,304
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25161484
Author URL: https://archiveofourown.org/users/Moon_Willow_23/pseuds/Moon_Willow_23
Summary: Alex Summers fell for Sean Cassidy almost instantly. Too bad no one told Sean before he put his foot in his mouth. Alex walked out of the Xavier mansion and into a series of unfulfilling and meaningless relationships, and Sean remained behind at the school teaching elementary school students. Twenty years and the Apocalypse incident since the two have said more than ten full sentences to one another, Alex returns to the school for Xavier's School for Gifted Youngsters' annual prom with a date, their family is determined to get them together once and for all.
Relationships: Alex Summers/Jean-Paul Beaubier (Briefly), Erik Lehnsherr/Charles Xavier, James "Bucky" Barnes/Original Female Character(s), Jean Grey/Scott Summers, Logan (X-Men)/Kayla Silverfox, Ororo Monroe/T'Challa (Background), Sean Cassidy/Alex Summers
Series: Galaxy Brain [2]
Series URL: https://archiveofourown.org/series/1822747
Kudos: 9





	Rewrite the Stars

**Author's Note:**

> "What if we rewrite the stars?/Say you were made to be mine/Nothing could keep us apart/You'd be the one I was meant/to find/It's up to you, and it's up to me/No one can say what we get to be/So why don't we rewrite the stars?/Maybe the world could be ours/Tonight..."
> 
> A/N: Hello, Sweets! So, this is the story of how Alex and Sean ended up together. I hope you have as much fun reading this as I did in writing it! Enjoy!

The annual Xavier’s School for Gifted Youngsters prom was in full swing. Unlike at most schools, the prom was open to all students, ranging in ages from five to eighteen. This year’s theme was entitled Starlight Symphony, and most of the partygoers were entranced by the music booming through the East ballroom. Sean Cassidy, the head of the school’s elementary and middle school program, was happily dancing with his fifteen-year-old adoptive sister Anya. Swirls of misty gray, sparkling fabric whipped about as they danced, and the sound of his sister’s laughter meant more to Sean than anything else. Then, the laughter stopped. Anya looked up at him with worry clear in her eyes, and he felt her push lightly into his mind.

**_“Alex just got here with his date. Can I go see him?”_** she asked telepathically, and Sean kissed her on the cheek.

“Go on, it’s fine. I’ll be alright, and he is legally your brother. I’ve just raised you alongside Mom and Dad is all.” he told her, the last bit coming out in a joking manner that earned him a slap on the shoulder and a kiss on the cheek before she took off towards the entrance hall.

“Sean, dance with me!” chirped a younger female voice from behind him, and the redhead turned to see Wanda, his and Anya’s ten-year-old sister, gazing up at him eagerly.

“Alright, baby bunny, let’s dance!” he said, shaking away the lingering thoughts of the blond Anya had run off to see as he led Wanda further into the middle of the dance floor.

Anya herself barreled into the entrance hall of the mansion calling out her second-eldest brother’s name. The blond looked up, smiled widely, and held his arms out for her. She crashed into him, glitter from her dress falling everywhere, and held on tightly. Alex hadn’t been home in almost six months since his assignment to the White Sands Testing Facility in New Mexico.

“You’re here!” she squealed, and Alex chuckled.

“Well, ya know, I was gonna skip this whole thing, but then some Bozo told me that I’d have some pretty sad sisters if I didn’t show.” he said, and she grinned up at him as they pulled away from one another.

“Remind me to thank Hank later; even Jean’s missed you, Alex! Of course, we’d all be sad if you skipped prom!” Anya replied, and a second man walked up beside the blond.

“Which is why I insisted that we make an effort to be here.” said the new man.

“Jean-Paul, what are you doing here?” Anya asked, quickly hugging the man while pretending that she didn’t know that he was there as Alex’s date.

“Well, when Alex told me about the Xavier’s prom tradition, I couldn’t let him attend without a date.” Jean-Paul Beaubier said, and Anya giggled.

“Speaking of dates, shouldn’t Barnes be around here somewhere? I haven’t had a good reason to use a plasma blast outside the Danger Room in a while.” Alex asked jokingly, and Anya leveled a glare at him.

“Bucky isn’t here. There’s something going on in Cairo that HYDRA needed him for, so he couldn’t make it this year. Before you got here, I was actually dancing with Sean, and I think Wanda nabbed him once I left.” she told him, and she noticed the way he swallowed when she said Sean’s name.

“I forgot he’d be here.” Alex tried to play off his tone as breezy and honest, but Anya rolled her eyes.

“Very breezy, Monica.” she said, and he shook his head at her.

“I am so not Monica; at the very least, I think I’d be Joey, maybe Chandler!” Alex retorted, and Anya snorted.

“If you say so, but if you’re interested in dates, you should be a good big brother and go check on Jean and Scott.” she teased, and Alex smirked.

“Don’t mind if I do.” he said before hurrying away to find the aforementioned pair.

“So, who’s this Sean?” Jean-Paul asked, and Anya sighed.

“Honestly, probably the reason you won’t get laid tonight. Sean is the Banshee and the man that Alex had been in love with since they met.” she told the Alpha Flight leader, patting him on the shoulder gently before leading him back towards the ballroom.

“And who is Bucky?” he asked.

“That would be my super-soldier assassin boyfriend.” she answered. “He and Alex are actually friends, despite what my brother just said.”

Anya slipped back over to where Sean and Wanda were while Alex was introducing Scott and Jean to Jean-Paul; she could feel the older mutant watching her as she made her way across the room, clearly looking for the man she’d said was the true object of Alex’s affections, so she sent a telepathic message to her parents. Charles and Erik, sitting at a table in a far corner of the room with almost-three-year-old Lorna, the youngest of Anya’s sisters, were content to watch the way the evening played out unless something dramatic occurred in which they would need to step in and remedy the situation.

As the night wore on, Alex and Sean both danced with numerous partners. Jean-Paul had gotten caught up in conversation with Logan and Kayla, excited to not be the only Canadian present, and had ended up leaving Alex to his own devices for most of prom. While Alex took his turn to dance with Anya, she watched as he gazed over at where Sean was dancing with Ororo and Darcy at the same time.

“Why won’t you just ask him out, Alex?” Anya asked, the longing near-radiating off the blond in large waves.

“Anh, you weren’t there the day I had myself tested. I’m not the kind of guy Sean’s interested in, I promise you.” Alex replied, ignoring his sister’s scoff.

“You know I’ve seen what’s inside his mind, so why would I tell you to do something that I knew would fail? It’s not like I get the same level of entertainment out of it that Emma gets. I just want you guys to be happy, and I can see that you’re not happy with Jean-Paul.” Anya told him. “Hell, I’m pretty sure that Scott could see that without rose quartz.”

“I can see it from inside a damn cryo-tank.” a thick Brooklyn accent came from behind Alex, and the blond sensibly stepped aside to allow his sister full access to the sharply dressed super-soldier who’d just arrived.

“I thought you were in Cairo!” she said happily as Bucky wrapped his arms around her.

“I was, but the job wasn’t as complex as I thought it’d be. I had some extra time, so I called for a lift via Air Kurt.” Bucky said, and the teleporter in question popped up beside them with a _bamf_ that was drowned out by the music.

“Gern geschehen, Ana Liebling.” Kurt said with a fanged smile before teleporting away once more.

“May I have this dance, doll?” Bucky asked, and Anya accepted, thus leaving Alex alone on the edge of the dance floor.

“Alex!” he heard Erik call, and the blond turned to where his parents were sitting with a large smile on his face.

“Dad!” he greeted the ferrokinetic with a hug before turning towards the telepath and the toddler in his lap. “Mom, Lor-Lor.”

“I have to do rounds, just to check that everything is as it should be, so would you kindly sit with your mother and sister for a moment?” Erik asked, and the blond nodded.

“Yeah, sure, no problem.” Alex agreed, taking Erik’s seat and turning his attention to Charles as his father stepped towards the outer edges of the dance floor. “He’s not just checking to make sure the punch hasn’t been spiked, is he?”

“You were a teenager when you realized that subtlety isn’t one of your father’s strong points, Alex.” Charles said bluntly, and the blond rolled his eyes.

“Why does everyone have an issue with my love life?” he asked, and Charles snorted.

“Sorry, but you call this a love life?” he replied. “Alex, you have never been happy in any of your relationships no matter how hard you try. Lying to me doesn’t work, and you know this already. Honestly, you tossed your chances at happiness out of a window the day you asked Hank to give you the test.”

“After seeing what you went through, I was curious. I just wanted to know, but I didn’t think that Sean would react like that.” Alex said, and Charles nodded.

“Dear, I know this. But I also know what you don’t because I know what Sean was thinking in that moment. Much like when you used to pick on Hank endlessly, words are not always the same inside as they are on the surface.” he said, and Alex gave him a curious look as Lorna climbed down from Charles’ lap and into his own.

“Mom, I’m going to need alcohol and for you to tell me what Sean was thinking when I got my results.” Alex said, and Charles offered him a small smile as a glass of top-shelf bourbon appeared on the table in a blur of silver.

“Pietro has been eager to show off for you now that he’s been practicing more, so do compliment him when you can actually see him.” Charles said quietly, and Alex chuckled as he briefly caught sight of the silver-haired speedster with his red-haired twin across the room.

“I’ve gotta clock that kid’s top speed before I leave out again.” he said to Charles before taking a swig from his glass and refocusing on the topic of Sean. “Now, what was he thinking?”

Across the room, Erik had found Sean trying to hide himself away near the dessert table. That being that “trying” was the operative word since Sean’s bright red hair caused him to stand out against the dark curtains covering the large windows. A slower song had started to play, and the redhead had seemingly extracted himself from the dance floor to watch as Anya, Darcy, and Ororo danced with Bucky, Dimitri, and the visiting Prince T’Challa of Wakanda.

“I believe that all three girls are fully capable of taking care of themselves, Sean.” Erik said to him, and the redhead chuckled.

“I don’t doubt that, but I wasn’t actually watching them.” Sean admitted, and Erik looked past the dance floor where he could just make out Jean-Paul Beaubier talking, borderline flirting, with one of the many alumni in attendance.

“Staring at his date isn’t going to make Alex aware of your feelings.” the older mutant said, watching as the younger man frowned.

“Alex and I have maybe said ten full sentences that weren’t hellos or goodbyes in as many years. I don’t think there’s really anything between us.” Sean said, rolling his eyes. “He’s your kid, and I’m sure that he’s happy with Jean-Paul, but he could do so much better than some shameless Canadian flirt.”

“You know, your sisters have been reading this book by Neil Gaiman recently, a book called _Stardust_ , and there’s a passage in this book that I think you would find relevant” Erik said after a moment. “A character in this book says ‘I know that love is unconditional. But I also know that it can be unpredictable, unexpected, uncontrollable, unbearable and strangely easy to mistake for loathing.’”

“Did you ever feel that way about Mom?” Sean asked, eyes flickering over to where Charles and Alex sat talking, little Lorna moving from one of their laps to the other.

“Oh, only every day. You see, our ideologies on how human-mutant relations should be are on complete opposite ends of the spectrum. We fight on this issue all the time, but we both know that the other will never change. However, despite the times we disagree, I could never truly love another the way I love him. He is my match, my missing piece, and I am the same for him. There is no one who pushes me harder or challenges me more, yet show me so much love and tenderness as Charles, not one.” Erik explained, and Sean smiled.

“So, what you’re saying is that Alex doesn’t hate me?” he asked, and the ferrokinetic gave a chuckle and a nod.

“Not just that, but also this, Sean: if you dislike Alex’s current taste in men, quit bitching about it and do something.” Erik said, patting him on the shoulder before finishing his walk around the room and returning to Charles, Lorna, and Alex.

“How’d it go, darling?” Charles asked, smiling as he saw his husband’s shark grin.

“It went well, though I suspect we should get our youngest three up to bed before too much longer. Where’s David?” Erik replied, and the younger telepath walked up with one of the twins holding onto each arm.

“Someone say bedtime for Little Lorna and the Twin Terrors?” David asked, and the twins began to plead to stay up later.

“There will be no arguments about bedtime tonight, little ones. We have a big day tomorrow, remember?” Charles said, and both twins’ eyes lit up at his words.

“We’re going Disneyland!” they chorused, and Erik cleared his throat prompting them to add. “And we’re going to see Tony!”

“You guys are going to have so much fun. Tell Tony I said hello?” Alex said to them, and they nodded together as they threw themselves into his open arms, Erik now holding Lorna.

“G’night, Alex!” Pietro told him before grabbing David’s hand and speeding the two of them away.

“Good night, Alex.” Wanda said, lowering her voice as she gave him a second hug. “I think Sean’s mad at Jean-Paul about something.”

Alex pressed a kiss to the top of her head before looking to Charles, who held out his hand towards his daughter while making eye contact with his son. He jerked his head backwards towards the balcony doors, and Alex gave a nod of understanding. Charles bid him goodnight along with Erik, and then Alex watched his parents leave with his three youngest siblings before making his way out onto the balcony where Sean and Jean-Paul seemed to be in the middle of an argument.

“I don’t care what kind of relationship you have with him, Alex deserves better than an over-flirtatious whore who makes eyes at every guy in the room.” he heard Sean snarl, choosing to stay in the shadows to watch how the argument progressed.

“Why, Banshee, one might almost think that you’re… _jealous_.” Jean-Paul responded. “I didn’t take you for the blond beefcake type.”

“Alex is one of my best friends, probably the first true friend I’ve ever had, and the things I would do to someone who hurt him…let’s just say there’s more to being a Banshee than just making noise.” Sean stated, and Alex smiled to himself.

“Ah, but would he wreak this much havoc for you?” Jean-Paul asked before turning to return to the party via the door on the other side of the balcony from Alex’s hiding spot, but a sharp whistle from Sean saw him toppling over the side of the balcony and disappearing for a few moments before floating back onto the balcony and aiming a punch at Sean that caused the redhead’s hair to fall from the knot it had been in at the base of his neck into a cascade of copper down his back as he dodged the hit. “That wasn’t very nice.”

“Don’t say I didn’t warn you, Northstar, just don’t.” Sean growled. “I swear, if you break his heart, I will break your eardrums. Try flying with a fucked-up equilibrium.”

Jean-Paul returned to the party at this point, brushing himself off and straightening his jacket before slipping into the room, but Sean remained on the balcony. Alex was about to go back inside himself, but then he heard Sean say his name. He froze in place.

“Alex, I can hear your breathing.” the super-sonic screamer said, and Alex stepped out from his hiding spot. “Why are you out here?”

“Wanda said she saw you come out here with Jean-Paul, and she thought that you guys were fighting. You know how much Wanda hates it when people fight.” Alex said, his eyes lingering on the length of Sean’s hair. “Your hair looks nice.”

“Could say the same about yours, Alex.” came the response. “Didn’t know they let you grow it out like that in the army.”

“I’m a researcher, so it stays tied back most of the time anyway.” Alex shrugged before continuing. “Did you mean what you said?”

“When? Tonight, or twenty years ago after the Apocalypse incident?” Sean asked.

“Both, but tonight specifically. Am I really your best friend?” Alex replied, and Sean gave him a nod.

“We lost Angel, Janos, and Darwin when they decided to not stick around full-time after Cuba; there’s no way in hell I’m close to Raven, and Hank isn’t even speaking English half the time, just science, so you’re all I’ve really got.” he admitted. “I stopped at elementary level science speak.”

“Hey, I speak fluent science!” Alex said in mock-offence.

“Yeah, but that’s more like a second language to you, not a first.” Sean joked before his tone shifted towards a more serious one. “Plus, you happen to be the only other one of us who was frozen that’s still here.”

“And I always will be, mo ghrá.” Alex told him, and Sean fixed him with a surprised stare.

“When did you learn that? Do you know what that means?” he asked, and Alex smirked.

“What, you didn’t think I’d turned into Hank and stared at varying forms of math and science all day, did you?” he said. “I, uh, _knew_ a couple of guys in Vietnam who were from Ireland, and I picked up on a few things.”

“After Apocalypse, why’d you leave? What did I do?” Sean asked, not expecting the blond to let out a tired sigh.

“You didn’t do anything, Sean, and never think that you did. I overheard you talking to Kurt, explaining my secondary mutation to him, and I took what I heard out of context. At the time, running was easier than actually talking.” Alex said, hating himself for making Sean take the blame for him leaving even unintentionally.

“Oh God, that wasn’t- I didn’t mean- You know that I would never-” Sean couldn’t form a complete sentence that summed up his thoughts accurately, so Alex cut him off.

“Mom set the record straight; it’s okay, I promise.” he said, moving closer to the redhead and leaning against the balustrade.

“Alex, I would never want you to feel that I- The idea that a guy like you would even be interested in a guy like me never even crossed my mind. When you got tested, I didn’t even know why you were bothering to do it. Not only would you not have to worry about the mutation ever being used, but you also wouldn’t be the one dealing with it in the first place as far as I knew. I didn’t even know you were into guys until that first Thanksgiving that you brought someone home with you.” Sean said, and Alex bit his lip nervously.

“Tell you a secret that I’m pretty sure Mom, Dad, Jean, Scott, Anya, Bucky, and Tony are the only ones who actually know? I brought that guy to Thanksgiving dinner because I realized that you didn’t know.” he admitted, and the two laughed.

“And your decision to go out with Jean-Paul? Real winner that one.” Sean remarked, but Alex shrugged.

“If he was with the right person, he’d settle down. He’d probably still be a flirt, but he wouldn’t do it seriously. I really only started seeing him so, on the off chance I let it happen, if I let him fuck me, I wouldn’t feel so bad if I accidentally said your name. He’d be so drunk after a party that he’d never know.” Alex admitted, and Sean’s eyebrows shot up at this.

“Alex, how much have you had to drink?” he asked, and the blond smiled softly.

“Not nearly enough.” he replied, and Sean stared at him. “I’ve had two glasses of bourbon, but that’s it. Lorna kept trying to take the glass from me, so I didn’t let it get refilled for a third.”

“So, you’re not even tipsy right now?” Sean asked, fighting back a smirk.

“Nope, not in the least. Why?” Alex replied. 

“Well, your date seems to have noticed that you’re out here with me. I just wanted to make sure you wouldn’t regret this in the morning before I quit bitching about your taste in men and actually did something about that.” Sean said before leaning over and lightly pecking Alex on the lips that Alex responded to by pulling him in for a proper kiss to which Sean was only too eager to reciprocate.

Alex woke the next morning to the sunlight streaming in through the window of his bedroom at the mansion. At least, he’d thought that it was his bedroom until he focused his eyes and saw the tartan curtains and emerald walls. He felt someone move beside him, and he looked to see Sean, a very naked Sean, sleeping on his stomach with his left arm thrown over Alex’s torso. Laying there, staring at Sean’s ceiling, memories of the night before flooded Alex’s mind, and he smiled as he remembered what finally being with the redhead had been like.

Turning his head slightly, Alex saw the earplugs on the nightstand and chuckled to himself. He wasn’t sure, but he thought that either Anya or Jean had ultimately been the one to tell Jean-Paul that Alex would be staying at the mansion alone the previous night; his memory only went as far as kissing Sean on the balcony that first time before becoming complete putty in the American-born Irishman’s hands. Dazed from the kiss, he’d let Sean guide him upstairs and into the sonic-screamer’s bedroom. Alex didn’t think that anyone, even Pietro, had ever gotten undressed as quickly as the two of them had managed once the door had been locked. It wasn’t rushed, forceful sex; rather, they took their time with one another. Alex had a distinct memory floating about of him having pulled Sean’s boxer-briefs off with his teeth; he’d gone slowly as he’d done so, and what he’d found had left him more than satisfied. Forty years’ worth of wondering had been well worth the wait.

“Definitely worth the wait.” Alex whispered to himself, mesmerized by the way the sunlight danced off Sean’s hair. “So damn beautiful.”

“Tell me how beautiful I am after coffee.” Sean grumbled, and Alex chuckled quietly as the redhead opened his eyes.

“I’ll tell you every chance I get, if that’s okay.” Alex said, and Sean pulled him close.

“Assuming we don’t get stuck inside magic green rocks where time moves backwards again, we aren’t exactly getting any younger. It’s more than okay, mo chroí.” the redhead told him, pressing kisses along Alex’s jawline and throat as he spoke.

“I thought you wanted coffee?” Alex joked as Sean shifted to where Alex was now lying beneath him.

“This is so much better than coffee.” Sean said, and Alex couldn’t help but agree.

Just over a month later, Alex and Sean were sitting in bed together, the latter enjoying having the former home for a while. It hadn’t been an expected visit, for Sean at least, when Alex showed up at the mansion and slipped into the back of the classroom where Sean was teaching his second graders the basics of their multiplication tables. Alex had greeted him with a kiss while the students were busy with their timed quiz, but he’d mentioned needing to meet with Hank and had disappeared until dinner that night. Now, they were both in bed, fully clothed, and reading work-related documents. Sean was grading the sixth graders’ final book reports, and Alex was reading a new project’s proposal.

“What was the appointment with Hank about earlier?” Sean asked as he marked Wanda’s report with a perfect score.

“Before I tell you, do you think we’re moving too fast?” Alex replied, setting his work and reading glasses on the bedside table, but Sean shook his head while laughing.

“Babe, you were my best friend for forty years before I started sleeping with you, and there’s not much left for us to find out about one another, so we can’t get much slower than we’ve been going.” Sean said, and Alex smiled.

“Okay, I deserved that one.” he said, taking a deep breath before continuing. “I’ve felt off for a few days, so I decided that I had to have Hank check something out for me. Turns out, I was right about what’s wrong with me.”

“Babe?” Sean asked worriedly, but Alex just gave him a reassuring smile and reached to take the red pen from his hand before answering.

“You’ve turned me into a damn teenage prom night cliché. Sean, all of Hank’s tests say that I’m six weeks pregnant.” the blond said, and he watched as Sean stood up from the bed and carefully moved his grading to the desk along the opposite wall before getting back into the bed, pinning Alex down by his shoulders, and kissing him deeply.

“Is breá liom an méid sin duit, a stór.” the redhead said breathlessly as they parted, and Alex smiled dopily up at him. “Pósadh liom?”

“Really? You’d really want to?” he asked, and Sean nodded.

“I wouldn’t ask if I wasn’t serious. Will you?” he asked again, and the blond pulled him for another kiss before answering.

“Yes, of course, I’ll marry you, Sean.”

**Author's Note:**

> Translations for This Chapter:  
> “Gern geschehen, Ana Liebling.” = "You're welcome, Ana dear."  
> mo ghrá = my love  
> mo chroí = my heart  
> “Is breá liom an méid sin duit, a stór.” = "I love you so much, darling."  
> “Pósadh liom?” = "Marry me?"


End file.
